Office 365 contains a variety of different applications. IT provides support on a standard selection of these apps. This selection is installed locally on employee machines via ‘Office 365 Pro Plus’ and is also available as Web Apps on https://www.office.com
In addition, Skype for Business is supported. Outlook will get more integration with other Office 365 services after the employee mailboxes has been moved from the local Exchange server to Office 365. This is scheduled to happen in 2020.
On office.com there are many more applications under the ‘All Apps’ arrow. If you want to use other apps you are on your own and must either use the “learning by doing” method or read up on Microsoft’s support pages here: https://support.office.com/
Office 365 falls under the category ‘Software as a Service’ which means that updates and feature changes will come much more often than was the case with the older, more static Office packages (which were typically renewed every 3 years)
Icons may change, new buttons appear or other design changes may occur up to several times a year.